Recent efforts of the coatings industry directed at the problem of volatile organic emissions of organic coatings have promoted the use of vinyl or acrylate monomers as reactive diluents. Reactive diluents are described by Emmons, Chemistry of High Solids Alkyd/Reactive Diluent Coatings, Jr. Coatings Technology 55, No. 702, July 1983, and in U.S. Pat. Nos. 4,014,830; 4,097,677; 4,145,503; 4,178,425; and 4,224,202. While the reactive diluent technology provides reduced solvent emission and high solids coatings, such systems have the disadvantage of slow dry and film cure on application. U.S. Pat. No. 4,304,883 (1981 to Hitachi) claims an unsaturated polyester resin composition prepared from dicyclopentadiene modified unsaturated alkyds (polyesters) containing allyl ethers and dissolved in a polymerizable vinyl monomer (styrene) and cured in the presence of air with organic peroxides.
Attempts to reduce the VOC content of alkyd paints via lower molecular weight and glass transition temperature (which give low VOC) have been shown to increase the film dry time. Other methods such as by incorporating benzoic acid are deceptive in that only a lacquer type dry results. In addition to film dry, it is desired to achieve solvent resistance, mechanical properties and weatherability. These and other advantageous properties result for the improved alkyd resins of the instant invention.